The present invention relates to data backup and recovery on computer systems.
Personal computer workstations, such as the IBM-compatible Personal Computer (PC), have become popular today for a wide variety of computing tasks. Each PC typically includes one or more internal high capacity hard disk drives, and operates under a disk operating system to control the internal operation of the PC. For IBM-compatible PC's, commonly used disk operating systems today are IBM OS/2 (commercially available from IBM corporation), Microsoft MS-DOS, and Microsoft Windows 3.x (both commercially available from Microsoft Corporation, Redmond, Wash.).
The complexity of personal computers has increased dramatically in recent years. A wide variety of hardware and software options are available today for configuring a personal computer, adding to their complexity. Complex computer systems require similarly complex disk operating systems to support the wide variety of possible system hardware and software configurations available today. Because there are so many possible system configurations available, a typical operating system needs to be individually tailored for each personal computer system on which it is installed. This tailoring operation typically requires that a skilled technician spend several hours building the operating system on the personal computer according to the desired system configuration. This process is typically repeated for each system built, even if the configuration of that system is identical to one previously built.
Data stored on magnetic media disk drives, such as high capacity hard disks, are vulnerable to hazards such as "head crashes," accidental exposure to magnetic fields, loss of power during data writing operations, unintentional reformatting or data overwriting, or other destructive forces which can cause stored data to be lost. Data can also be lost by software failure, user error, hard storage device failure, or even loss or theft of the storage media or device.
Data backup systems, such as magnetic tape backup, are generally very useful for restoring corrupted or destroyed data files on the high capacity hard disk. However, these backup systems normally require that the disk operating system installed on the hard disk be intact and fully operational before data can be restored to the hard disk. A data loss affecting the operating system itself is typically not recoverable by using the tape backup system, and requires that the operating system be reloaded onto the hard disk and configured anew. Where the operating system was "factory loaded," reloading of the operating system onto the hard disk outside the factory may consume many hours of valuable user and technical support time.
Data backup systems are known which restore high capacity hard disks from a digital image of that hard disk, i.e., on a media bit-mapped basis. This type of image restoration may be able to restore an operating system to fixed storage media since the operating system is simply some portion of the total image being restored. However, any reformat or repartition of the hard disk, which is typically required after a head crash or other problem affecting the integrity of the media, can change the underlying logical structure of the hard disk which may make it impossible to restore a digital image to the hard disk without losing data.